It is a main problem that environment can be polluted by discharge of wastewater containing NH4+, Ca2+ and Na+, when rare earths (REs) are extracted in a saponified system using di-(2-ethylhexyl) phosphoric acid (D2EHPA). Pointing to this problem, the selective separation of Pr(Ⅲ) by liquid–liquid extraction using D2EHPA in the presence of a complexing agent of lactic acid (LA) has been studied. Results are shown that the maximum of separation factor (β) between Pr/Ce is 2.04 and extraction selectivity is also enhanced when compared with that of D2EHPA–HCl system. The thermodynamic function △H is determined as exothermically driven. The cation exchange mechanism is discussed by IR spectra. Thus, the results suggest that highly selective separation and extraction of Pr(Ⅲ) from a Pr/Ce solution is possible, providing a simple and environment-friendly complexing method for extraction-separation rare earths, and promoting the sustainable development in rare earths practices.of Pr(Ⅲ) from a Pr/Ce solution is possible, providing a simple and environment-friendly complexing method for extraction-separation rare earths, and promoting the sustainable development in rare earths practices.

A new hot dip Zn-5%Al-0.3%Mg alloy coating was performed on cold rolled common steel. The hot-dip process was executed by self-made hot dip galvanising simulator (China patent, No.201010160353). The corrosion resistance of alloy-coated steels was detected by neutral salt spray test . SEM and EDS test results demonstrate that Mg is mainly distributed in the crystal boundary. XRD test results shows corrosion product of Zn-5%Al-0.3%Mg alloy coating is mainly Zn5(OH)8Cl2•H2O. The characteristic of Zn5 (OH)8Cl2•H2O is dense and insoluble, so it is protective. In order to study the anticorrosion mechanism, all the tests of the Zn-5%Al-0.3%Mg alloy were carried out with Zn-5%Al coating together.

The connection characteristics and methods of ceramic and metal were studied, and emphatically the current research status of ceramic and metal active brazing, diffusion welding, self-propagating high temperature synthesis welding, fusion welding, friction welding, ultrasonic welding, hot-press reaction sintering welding and other welding methods were introduced. The main problems and improvement methods existing in the current ceramic and metal welding are discussed, and the development trend of ceramic and metal brazing connection is prospected.

Bastnaesite was activated at a temperature, and then the rare earths carbonate of the minerals was leached by HCl solution. When activation temperature was 400°C, activation time was 3h, HCl concentration was 3 mol•L-1, leaching temperature was 90°C, liquid to solid was 20:1, the leaching ratio of rare earths carbonate and rare earths fluoride was 94.6% and 0.07% respectively. The results of XRD and SEM showed that bastnaesite was powdered and coarseness in activation process, which made the leaching of rare earths carbonate by HCl solution become easy. The main components of leaching slag were rare earths fluoride, calcium fluoride and barium sulfate.

Hot-dip galvanized steels are widely used in modern industry. The corrosion resistance and formability of them are closely related to the thickness and cross section microstructure of the hot-dip coating. In this paper, the effects of Si and RE on the thickness of Zn-6Al-3Mg alloy coating (ZAM) were investigated. Steel sheets were coated by using an experimental hot-dip galvanizing simulator. The thickness and cross section microstructure of ZAM coating alloyed with different content of Si and RE were characterized by using optical microscope and SEM, and element distribution was study by EDS. The results demonstrated that the reaction between Al from the bath and Fe form the steel sheets was suppressed by the addition of 0.1 wt. % Si to the Zn-6Al-3Mg bath, and the addition of RE effectively decreased the thickness of coating by means of improving the flowing property of the zinc alloy bath. Under the combined effects of Si and RE, the thickness of Zn-6Al-3Mg alloy coating went down from 33 μm to 10.1 μm.